[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: RATITES AND BROODING



>Yep. I can hardly wait for the more-thorough molecular data which will nail
>down every bird's relation with every other without ambiguity (I'm not
>kidding). But that day is probably ten years off. Until then, I accept your
>assessment that relationships are ambiguous enough for doubt. But, especially
>with the ostrich in the mix, the case for basal wing-feather brooding bears,
>at the least, some watching and consideration.
>    Tom Hopp

I am still curious to hear why this is so when all other ratites (tinamous
excepted) have greatly reduced wings unsuitable for brooding.  Of course if
we assume ratites evolved from flying ancestors (a seemingly inescapable
conclusion) you can certainly argue that wing-brooding may have been
present, but secondarily lost, in emus, rheas, cassowaries and kiwis.  The
question I have is not whether such behaviour is "basal", but why, if it is
so important, these birds have not retained larger wings?  It would strike
me that a behaviour of such selective importance that it purportedly drove
the evolution of wing-feathers in the first place would hardly have been so
easily abandoned (and abandoned repeatedly as secondary flightlessness
evolved separately in may bird lines).


--
Ronald I. Orenstein                           Phone: (905) 820-7886
International Wildlife Coalition              Fax/Modem: (905) 569-0116
1825 Shady Creek Court                 
Mississauga, Ontario, Canada L5L 3W2          mailto:ornstn@home.com